Two principal projects will be carried out under this research grant: (1) A study of the processing of color information by cells in the primate visual cortex. One of the continuing puzzles as to the organization of the visual system is the fate of color information in the visual cortex. A very large percentage of the cells projecting from the cortex carry color information, yet little evidence has been found for responses to color among cells in the cortex. This problems has to some extent been solved by the discovery of the class of cells that we have termed universal color cells that clearly are putting together both black/white and color information. There must, in addition, be stages of processing of pure color information. We have found evidence for such stages, as have others, but their nature has yet to be understood.(2) The spatial processing of information in the lateral geniculate and visual cortex. We propose to investigate this by looking at the responses of single cells to modulations in both the spatial and temporal domains. We will record responses to spatial sine and square waves in figures of other complexities, and, in addition, record responses of cells to sinusoidal temporal modulation. We will attempt to understand how spatial information is progressively processed by the visual system.